Package io.atomix.utils.memory

Class MappedMemoryAllocator

java.lang.Object

io.atomix.utils.memory.MappedMemoryAllocator

All Implemented Interfaces:

MemoryAllocator<MappedMemory>

public class MappedMemoryAllocator
extends Object
implements MemoryAllocator<MappedMemory>

Mapped memory allocator.

The mapped memory allocator provides direct memory access to memory mapped from a file on disk. The mapped allocator supports allocating memory in any FileChannel.MapMode. Once the file is mapped and the memory has been allocated, the mapped allocator provides the memory address of the underlying MappedByteBuffer for access via Unsafe.

Author:

Jordan Halterman

Field Summary

Fields

Modifier and Type	Field	Description
static FileChannel.MapMode	DEFAULT_MAP_MODE

Constructor Summary

Constructors

Constructor	Description
MappedMemoryAllocator(File file)
MappedMemoryAllocator(File file, FileChannel.MapMode mode)
MappedMemoryAllocator(File file, FileChannel.MapMode mode, long offset)
MappedMemoryAllocator(RandomAccessFile file, FileChannel.MapMode mode, long offset)

Method Summary

Modifier and Type	Method	Description
MappedMemory	allocate(int size)	Allocates memory.
void	close()
MappedMemory	reallocate(MappedMemory memory, int size)	Reallocates the given memory.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DEFAULT_MAP_MODE

public static final FileChannel.MapMode DEFAULT_MAP_MODE

Constructor Detail

MappedMemoryAllocator

public MappedMemoryAllocator(File file)

MappedMemoryAllocator

public MappedMemoryAllocator(File file,
                             FileChannel.MapMode mode)

MappedMemoryAllocator

public MappedMemoryAllocator(File file,
                             FileChannel.MapMode mode,
                             long offset)

MappedMemoryAllocator

public MappedMemoryAllocator(RandomAccessFile file,
                             FileChannel.MapMode mode,
                             long offset)

Method Detail

allocate

public MappedMemory allocate(int size)

Description copied from interface: MemoryAllocator

Allocates memory.

Specified by:

allocate in interface MemoryAllocator<MappedMemory>

Parameters:

size - The count of the memory to allocate.

Returns:

The allocated memory.

reallocate

public MappedMemory reallocate(MappedMemory memory,
                               int size)

Description copied from interface: MemoryAllocator

Reallocates the given memory.

When the memory is reallocated, the memory address for the given Memory instance may change. The returned Memory instance will contain the updated address and count.

Specified by:

reallocate in interface MemoryAllocator<MappedMemory>

Parameters:

memory - The memory to reallocate.

size - The count to which to reallocate the given memory.

Returns:

The reallocated memory.

close

public void close()